Compiler Error CS0202

foreach requires that the return type 'type' of 'type.GetEnumerator()' must have a suitable public MoveNext method and public Current property

A GetEnumerator function, used to enable the use of foreach statements, cannot return a pointer or array; it must return an instance of a class that is able to act as an enumerator. The proper requirements to serve as an enumerator include a public Current property and a public MoveNext method.

The following sample generates CS0202:

// CS0202.cs

public class C1
{
   public int Current
   {
      get
      {
         return 0;
      }
   }

   public bool MoveNext ()
   {
      return false;
   }

   public static implicit operator C1 (int c1)
   {
      return 0;
   }
}

public class C2
{
   public int Current
   {
      get
      {
         return 0;
      }
   }

   public bool MoveNext ()
   {
      return false;
   }

   public C1[] GetEnumerator ()
   // try the following line instead
   // public C1 GetEnumerator ()
   {
      return null;
   }
}

public class MainClass
{
   public static void Main ()
   {
      C2 c2 = new C2();

      foreach (C1 x in c2)   // CS0202
      {
         System.Console.WriteLine(x.Current);
      }
   }
}